How poverty's effects on brain development make it harder for poor children to learn

July 21, 2015

MADISON—A study published Monday in JAMA Pediatrics reveals for the first time the mechanism behind the relationship between childhood poverty and doing poorly in school.

Barbara L. Wolfe, Seth D. Pollak, Nicole L. Hair, & Jamie L. Hanson

In their analysis, researchers Nicole Hair, Jamie Hanson, Barbara Wolfe, and Seth Pollak show how the brain development delays found in children growing up in poverty inhibit the ability to learn and do well in school.

Past studies have demonstrated that children raised in poverty have smaller brain volumes than developmental norms in the parts of the brain that control functions necessary for learning, and the poor academic and cognitive outcomes of children living in poverty have been well known for decades. But Hair and colleagues' groundbreaking research shows how the structural brain development deficits of growing up in deprivation impair children's school performance.

The findings were striking. In the words of co-author Seth Pollak of the University of Wisconsin–Madison, "It was stunning to see the circle closed—the delay in brain growth explains the achievement deficit in poor children."

"Our research suggests that specific brain structures tied to processes critical for learning and educational functioning (e.g., sustained attention, planning, and cognitive flexibility) are vulnerable to the environmental circumstances of poverty, such as stress and limited stimulation and nutrition," the authors note in their article.

Using data from the National Institutes of Health Magnetic Resonance Imaging Study of Normal Brain Development, the investigators looked at MRI brain scans over time of a diverse group of children and adolescents from a range of socioeconomic backgrounds. Children facing other risk factors for compromised brain development were screened out of the sample.

The poor children's MRIs displayed systematic differences in the frontal lobe, temporal lobe, and hippocampus from the middle-class children, despite the high level of education of 85 percent of the parents in the sample.

The effects were most pronounced among the poorest children. Children living 1.5 times below the federal poverty level had smaller regional volumes of gray matter, 3 to 4 percentage points below developmental norms. But the gap of children living below the federal poverty level was much larger, 8 to 10 percentage points lower.

The researchers say that the developmental differences in the frontal and temporal lobes likely account for as much as 20 percent of low-income children's achievement deficits when compared to their more-advantaged peers.

Why does poverty impair brain development? Study coauthors believe it is the adversities typical of growing up in poverty—elevated levels of stress, less parental nurturance, more family instability, and greater exposure to violence—that cause the developmental delays.

The findings provide further evidence that early childhood is a critical period of brain development in children. The authors point to the importance of early policy interventions that put poor children on a more even playing field with their peers from financially comfortable backgrounds.

Study coauthors are Barbara Wolfe, the Richard A. Easterlin Professor of Public Affairs, Economics, and Population Health Sciences and an executive committee member and former director of IRP at the University of Wisconsin–Madison; Seth Pollak, the College of Letters and Science Distinguished Professor of Psychology and Professor of Anthropology, Pediatrics, Psychiatry, and Public Affairs, Laboratory Director of the Child Development Lab, Waisman Center, and an IRP faculty affiliate at UW–Madison; Nicole Hair, a Robert Wood Johnson Foundation Scholar in Health Policy at the University of Michigan, Ann Arbor, participated in the IRP Graduate Research Fellow training program and earned her Ph.D. from UW–Madison in 2014; and Jamie Hanson, a postdoctoral fellow at the Center for Developmental Science at the University of North Carolina at Chapel Hill and in the Laboratory of Neurogenetics at Duke University, he earned his Ph.D. from UW–Madison in 2014.

See also an editorial, "Poverty's Most Insidious Damage: The Developing Brain," in JAMA Pediatrics by Joan L. Luby written in response to the Hair and colleagues findings.

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—Deborah Johnson, djohnson@ssc.wisc.edu, (608) 262-7779

 

Read More

Association of Child Poverty, Brain Development, and Academic Achievement, July 20, 2015, JAMA Pediatrics

Poverty's Most Insidious Damage: The Developing Brain, editorial by Dr. Joan L. Luby written in response to the findings, July 20, 2015, JAMA Pediatrics

Poverty May Hinder Kids' Brain Development, Study Says, July 20, 2015, U.S. News and World Report

Brain Scans Reveal How Poverty Hurts Children's Brains, July 20, 2015, Bloomberg Business

What Poverty Does to Kids' Brains, July 20, 2015, Mother Jones

Pobreza prejudica o desenvolvimento do cérebro na infância Diário de Notícias [Poverty Impairs Brain Development in Childhood], 22 Jul 2015, Daily News

Differences in brain structure development may explain test score gap for poor children, July 20, 2015, Science Daily

How Poverty in America Negatively Affects A Child's Brain Development, 21 Jul 2015, Parent Herald

La pobreza perjudica el desarrollo del cerebro en la infancia [Poverty impairs brain development in childhood], 21 July 2015, El Pais [Spain]

Poor Students Have Lower Test Scores Than Wealthier Ones: Study, 21 Jul 2015, Latinos Health

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